Typically, alerts are triggered on an aircraft in response to a physical system failure. Such alerts merely notify a pilot that the system has failed and may not provide any guidance as to that system's relevance to the continued safe operation of the aircraft.
An aircraft comprises a large number of interconnected sub-systems that may co-operate as a highly integrated system to enable the complete functionality of the aircraft. Since many sub-systems are connected with others, when a sub-system fails, it can be very difficult for a flight crew to ascertain how that failure will propagate through the aircraft and affect overall functionality.
For example, the failure of a sub-system for sensing radar altitude can affect the correct functioning of an auto-throttle system and thrust reversers and affect the function of stopping on the ground, while loss of a sub-system for providing hydraulic pressure can affect the operation of ground spoilers, wheel braking, reverse thrust and rudder yaw control and thus affect the functions of stopping and steering on the ground.
System integration levels are increasing on newer system, increasing the burden on the operator to reason through the effects of a sub-system failure. Accordingly, there is a need to provide an alert system that aids the (operator) pilot in knowing how the sub-system failures remove or degrade important system-level or aircraft functions.